There are articulated tracked vehicles which have a front and rear vehicle portion which are linked together controllably by means of a control gear. The vehicle comprises one or more drive motors, which, via a power transmission, distribute the power from the engine or engines to a respective track of the vehicle.
Document WO-A1-00/35735 shows a control gear for coupling a first and second vehicle portion of an articulated vehicle. The control gear comprises two control links, which are articulately connected to one another by means of a control joint. The control gear further comprises two control cylinders, which have the task of changing the position of two vehicle portions in relation to one another for the purpose of changing the transport direction of the vehicle. The control gear also comprises two hydraulic piston cylinder units, which are configured as combined pressurizable actuating cylinders and hydraulic dampers for damping vertical swinging movements between the vehicle portions during transport and for, where necessary, for example, lifting and angling the vehicle portions upwards in order to pass an obstacle.
When articulated vehicles of the above-stated type are subjected to external influence, such as detonation of a mine, a movement is induced in the vehicle portions. This movement reaches a speed and acceleration which is proportional to the weight of the vehicle portions. When the vehicle is subjected to a detonation, the impact on vehicle and personnel in the vehicle occurs in two phases. The first phase arises when the charge detonates, which lasts for a few milliseconds. Then a pressure wave propagates from the charge and towards the vehicle, whereupon the high pressure from the pressure wave hits the vehicle. The vehicle is deformed by the pressure from the pressure wave and the size of the deformation is dependent on the design and structure of the vehicle and on the distance of the charge from and placement of the charge in relation to the vehicle. The movement of the vehicle during the first phase is small and can amount to just a few mm. However, the vehicle acquires an acceleration and a speed in the direction away from the detonation. Personnel present inside the vehicle can injure body parts which are close to or are in contact with the parts of the vehicle which are deformed. Moreover, a pressure increase which occurs inside the vehicle due to the detonation injures personnel present inside the vehicle.
The second phase is started once the vehicle has gained the initial speed during the high acceleration and the small movement during the detonation phase, and is concluded when the vehicle comes to rest. This phase often involves large movements of the vehicle, which results in the vehicle being able to be thrown several meters. When the vehicle is dislodged, the personnel inside the carriage can be injured.
Since the sizes of the acceleration, speed and movements which are induced in the vehicle in the event of a detonation are proportional to the weight of the vehicle, it is desirable to utilize the whole weight of a vehicle when this is subjected to a detonation. An articulated vehicle does not however make use of the whole of the vehicle weight in a detonation, since the control gear acts as a rotatable link between the vehicle portions.